A 2,500 ft² roof can catch about 46,000 gallons of rain a year in our climate. What you spend to hold it depends on a handful of choices — and the real number is set at the free Site Read.
~46,000 gal/yr per 2,500 ft²Rebate-eligible (SAWS)Free Site Read
Rainwater harvesting is the rare upgrade where the resource is free and the only question is how much of it you decide to keep. The cost isn't one number off a webpage — it's the sum of a few choices about size, tanks, and plumbing.
So we'll do this the honest way. First, what you're actually catching off your roof. Then the things that move the price, qualitatively, with no invented figures. The dollar amount is set on-site, at the Site Read, after we measure your roof and your slope.
§ 1 · The yield
What you're actually catching.
Start with the resource, because most people underestimate it badly. A 2,500 ft² roof can yield about 46,000 gallons of capturable rain per year in our climate. That water is already falling on your house — right now it runs off the eaves, down the drive, and into the street.
That 46,000-gallon figure is the ceiling. It's not the size of your tank; it's the size of the opportunity. Your cistern is a decision about how much of that yearly yield you want to hold and put back into your beds instead of letting it leave the property. A bigger roof catches more. A bigger tank keeps more. Everything else is detail.
§ 2 · What moves the price
What drives the cost.
Cistern size. Storage capacity is the single biggest driver. A few hundred gallons in a barrel and several thousand in a buried tank are different projects entirely.
Above-ground vs buried. A tank set on a pad is the simplest install. Burying it adds excavation and structure — but buys you back the yard and hides the system.
First-flush diverter. The piece that dumps the dirty first wash off the roof before clean water reaches the tank. It's how you keep stored water usable.
Gravity-fed vs pumped. If your slope lets water move on its own, you skip a pump. If it doesn't, distribution needs one — and that adds equipment and power.
Ties into irrigation. A tank that just stores water is cheaper than one plumbed to feed your beds on demand. Whether it connects to irrigation changes the scope.
None of those carry a fixed price, because the right answer depends on your roof and your slope. That's exactly what the Site Read is for — we set the real number on-site, not off a page, backed by a full Land Report of your ground that measures the roof, the fall, and where the runoff is going now.
§ 3 · The rebate angle
The rebate angle.
In San Antonio, SAWS offers rebates for rainwater harvesting systems. That changes the math — part of what you'd spend on the system comes back. We design the system to qualify: sizing, components, and documentation built to meet the program from the start rather than retrofitted after the fact.
We won't quote you a rebate figure we can't source. The current number gets confirmed against the program before it goes in your plan. Outside the SAWS service area, we check for local programs where eligible — the same design-to-qualify approach, applied to whatever's on offer in your area.
It depends on the drivers: cistern size, whether the tank sits above ground or buried, whether you add a first-flush diverter, whether the water is gravity-fed or pumped, and whether it ties into irrigation. A 300-gallon rain barrel and a buried 5,000-gallon cistern that feeds your beds are not the same project. We don't quote a number off a webpage — the real price is set at the free Site Read, after we measure your roof, your slope, and where the water needs to go.
How much rain can I actually catch?
A lot more than people expect. A 2,500 ft² roof can yield about 46,000 gallons of capturable rain per year in our climate. That's the ceiling on what's worth storing — your cistern size is a decision about how much of that 46,000 gallons you want to hold instead of watching it run off into the street.
Are there rebates in San Antonio?
Yes. SAWS offers rebates for rainwater harvesting systems in San Antonio, and we design the system to qualify — sizing, components, and documentation built to meet the program rather than retrofitted after. Outside the SAWS service area we check for local programs where eligible. We won't quote you a rebate figure we can't source; we confirm the current number against the program before it goes in your plan.
Is the estimate free?
The first Site Read is $300, credited — free when you build — a 60-to-90-minute on-site reading of your roof, your slope, and where the water needs to go, plus a written plan and price range within 48 hours. It's the honest version of an estimate: you get a real number and a real plan whether or not you build with us.
From first look to built
Three steps. No leap of faith.
Start free. See your property in 3D before you spend a dollar on the build. Then build it for a number you can see coming.
01 · Free
Preliminary Read.
We come read your property — soil, water, light, the lay of the land — and sketch a direction. Credited in full, no obligation.
02 · $300, credited in full
3D LiDAR Design.
A drone-LiDAR scan and a measured 3D design — exactly where the water flows, drawn to the inch. The $300 comes off your build.
03 · Priced clear
We build it.
Curbside bioswales from $300 a linear meter, plus fountains, native landscapes, and water systems — built by the same hands. No surprise numbers.